Indirectly illuminated sign

ABSTRACT

An internally illuminated sign having indirect illumination provided by light emitting diodes (LED). A plurality of LED&#39;s are mounted on a printed circuit board (PC board) and mounted within the sign. The PC board is offset to a side of the sign housing with the somewhat directional LED light source directed toward a reflector. The reflector is angled to convert the generally narrow directional light source of an LED into a substantially even, diffused and non-uniform light distribution pattern.

FIELD OF INVENTION

The present invention relates to illuminated devices and, moreparticularly, to an LED illuminated sign such as, for example, aso-called exit sign.

BACKGROUND OF INVENTION

Typically, lighted signs such as are utilized for indicating an "exit",or "fire escape" and the like, generally include a transparent ortranslucent colored lens or cover screen interposed in front of at leastone florescent or incandescent bulb. Such devices, however, requirerelatively expensive and frequent maintenance, i.e., bulb replacement,provide noticeably pinpoint light source and high operation cost.

Some conventionally lighted signs use bulbs to either form the word(s)or are arranged contiguously in alignment with the transparent wordportions of the sign. Obviously, the letters in the sign in front of thebulbs appear much brighter than those portions spaced further from thebulb, the result being an inefficient, relatively expensive andesthetically unpleasant illuminated sign. In addition, the burnout ofone or more such bulbs is typically noticeable by observers andinformation distortion may result.

These devices have numerous deficiencies such as being sumptuous incomponent parts, being cumbersome in design, requiring considerablemaintenance, and subject to failure, and are relatively expensive andcomplex to manufacture.

PRIOR ART STATEMENT

In a number of prior art devices, such as described in U.S. Pat. Nos.3,402,494 issued Sep. 24, 1968 to Raymond L. Gray; and 3,310,670 issuedMar. 21, 1967 to Ronald W. Sheppard; and 1,944,276 issued to LindseySchepmoes; the use of incandescent bulbs within an exit type sign isdisclosed.

Another patent reference of interest is U.S. Pat. No. 3,309,806 issuedMar. 21, 1967 to R. S. Gallagher. This prior art "exit" sign uses aplurality of light bulbs arranged in rows and columns parallel with adiffusing plate and a lens plate. Although this device may present someadvantages over the incandescent sign devices noted above, this typesign (design) is flawed in that such bulb arrangements can result innoticeable bulb burnout(s) and requires relatively numerous bulbs due tothe light retarding effect of the diffusing plate.

Other prior art patents of interest include: U.S. Pat. Nos. 5,018,290issued May 28, 1991 to Edward P. Kozek and Charles R. Ruskouski;3,957,351 issued May 18, 1976 to Glade M. Stockwell; and 4,768,300issued Sep. 6, 1988 to Renzo N. Rutili.

The above noted patents are mentioned as being representative of theprior art and other pertinent references may exist. None of thesepatents are deemed to affect the patentability of the present claimedinvention.

In contrast to the prior art "exit" type signs typically used inbuildings to meet local fire and building codes, the present inventionprovides a relatively low cost sign which uses low energy consumingLED's mounted on a printed circuit board and located at one or moresides of the housing to provide a source of relatively directional lightwhich is then converted or reflected to simulate a diffused light sourcebehind the transparent or translucent word portions of the sign.

SUMMARY OF THE INVENTION

An illuminated sign construction comprising: a housing having an openside wall, a sign cover plate having indicia and/or wordsdemarcated/defined by translucent sections of plastic or glass or thelike, a plurality of light emitting diodes mounted within said housingin back-of or posterior to the non-translucent or opaque portions of thesign cover plate, and a reflector plate or member for reflecting anddiffusing the somewhat directional light being emitted by the LED's intoa relatively diffused field of light illumination through the signindicia to thereby present substantially uniformly illuminated signindicia and/or words.

OBJECTIVES

Accordingly, it is an object of the present invention to provide a newand improved illuminated type sign.

Another object of the present invention is to provide a new and improved"exit" type sign.

Another object of the present invention is to provide a new and improvedilluminated directional sign.

Another object of the present invention is to provide a sign apparatusthat provides a substantially uniform field of illumination from aplurality of LED's offset within the sign apparatus.

Another object of the present invention is to provide an illuminatedtyped sign being relatively less expensive to manufacture.

Another object of the present invention is to provide a sign apparatuswhich is relatively less complex to manufacture.

Another object of the present invention is to provide a relatively lightweight, durable, less energy consumptive and long lasting "exit" typesign for whatever sign symbols are desired.

Another object of the present invention is to provide an LED illuminatedsign adapted to enable signs of different designations interchangeablewithout rearrangement or dislocation of the mounted LED light source.

Another object of the present invention is to provide a sign which usessubstantially less energy to illumimate an "EXIT" type sign thancurrently available "EXIT" signs.

It is yet another object of the invention to provide a sign having areflector and diffuser means for substantially converting the virtualunidirectional light emitted from LED's into a source of substantiallydiffused light radiating from the sign indicia.

The invention possesses other objects and features and advantages, whichwill be set forth in the detailed description of the preferredembodiments of the invention. It is to be understood, however, thatvariations of the illustrated embodiments may be achieved which arewithin the intended scope of the claimed invention.

BRIEF DESCRIPTION OF THE DRAWINGS Throughout the drawings, likereference numerals refer to like parts.

FIG. 1 is a perspective view of a sign embodying the present invention;

FIG. 2 is a cross sectional view of the sign illustrated in FIG. 1showing the offset or offstaged LED printed circuit board and reflectorassembly in accordance with the invention;

FIG. 3 is a cross sectional view of an alternative embodiment of asingle sided sign in accordance with the invention;

FIG. 4 is a cross sectional view of an alternative embodiment of theinvention illustrating a double sided type sign;

FIG. 5 is a cross sectional view of an alternative embodiment of theinvention depicting a double sided sign;

FIG. 6 is a front plan view illustrating a possible arrangement formounting the LED's in accordance with the invention; and

FIG. 7 is a perspective view of a reflector member having a specular orknurled reflective surface in accordance with the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings in which like numerals indicate like-parts,particularly FIGS. 1 and 2 there is shown an "exit" type signconstructed in accordance with the invention to have a simple assemblycomprising a housing 10, a sign plate 11, a printed circuit board 12 (PCboard) having a plurality of light emitting diode (LED) lights 13, and areflector plate 14.

In general, the housing 10 has a pair of spaced side walls 15, 16, aback wall member 17, a top wall member 18, and a bottom wall member 19.The housing 10 may be formed of plastic, metal or other suitablematerial and being conventionally dimensioned for the selected use suchas an "exit" sign used in buildings according to local code. Basically,such signs have a rectangular or box shape of a size to accommodate adisplay panel or cover plate 11 of desired dimensions. The enclosure orhousing 10 has an open front wall portion being defined by wall portions15, 16, 18 and 19. It will be appreciated that the structure asdescribed thus far can be utilized to provide an illuminated display ina generally conventional manner whereby light passes through thetranslucent legend 20 and is blocked by the opaque or non-transparentportions 21 of cover plate 11, to illuminate and define, for example,the word "EXIT". The cover plate 11 may be formed of a flat sheet oftranslucent plastic and having a rectangular shape and dimensioned forbeing affixed to the housing 10 over the front open wall portion definedby walls 15, 16, 18, 19. The housing wall sections defining one or moreholes 47 to enable one or more downwardly directed beams of light rays44 to exit the housing.

In accordance with the present invention, a printed circuit board 12with a plurality of light emitting diodes 13 mounted thereon isaffixed/mounted in conventional manner to a side wall member 16 ofhousing 10. The PC board 12 may have an obtuse or acute angularityrelative to the longitudinal axis of the enclosure. And a reflectormember or plate 14 is mounted within housing 10 for reflecting the lightoutput 22 from the LED's 13 unto the bottom surface 23 of,cover plate 20and through the transparent sections 24 of the indicia/legend 20.

The LED's 13 may be mounted onto the PC board 12 and electricallyactuated/energized in conventional manner. Accordingly, an electricaldiagram or schematic and LED bulb mounting fixture details are omittedto avoid prolixity. Basically speaking, however, the PC board 12 may beaffixed to side wall member 16 of housing 10 by conventional nuts andbolts 26.

As is generally recognized, LED's 13 when energized produce a relativelynarrow band 22 of somewhat directional light beams 25. It is this narrowband of directional light characteristic which prior to the presentinvention caused sign manufacturers to avoid their use in such signs.

An important feature of the present invention is the provision of areflector 14 mounted within housing 10. Reflector 14 may be formed of apolished metal or other suitable material to have a reflective surface28. The reflective surface 28 may be smooth or specular or knurled orother suitable surface finish so as to reflect and diffuse the beams 22of light 25 within housing 10 and, thereby, provide a diffused anduniform illumination through the transparent legend sections 20. In thismanner, the benefits of a low energy consuming LED light source isconverted into a substantially uniformly diffused/scattered light withinthe "EXIT" type sign. The reflector plate member 14 may be dimensionedto accommodate the size of the sign legend 20 so as to efficientlyutilize the available beams of light 25 which may be substantiallydirected onto the reflector plate within housing 10. Reflector 14, asshown in FIGS. 2 and 7, may comprise a rectangular flat sheet ofpolished metal having an upturned or bent section 29.angled to reflectlight rays upwardly onto the cover plate 11.

Referring now to FIG. 3, a first alternative embodiment of the sign andreflector shown in FIG. 1 are illustrated. All other components andoperations remain basically the same. The rear or bottom wall 30 ofhousing 31 comprises a square or rectangular shaped wall member 30having a bent or inclined end portion 32 contoured for reflecting lightrays 25 upwardly toward the legend cover plate 11. The inside of thebottom wall 30 is treated to yield a high reflectance specular or apolished knurled finished reflector 33. The specular or knurl reflectivesurface is illustrated by bumps 34. Since the technology for forming areflective specular or knurl surface is within the prior art, a moredetailed discussion of the method of forming such a surface 33, 34 onthe housing bottom wall 30 is omitted to avoid prolixity. The endsection 32 of the reflector back panel 30 may contain one or more holes35 to enable light rays 36 to radiate without said housing end section32. The holes 35 may be formed on the top end section 32 (see FIG. 3)and/or at the bottom 16 (see FIG. 1) of the sign 10, 40. In this mannerpartial lighting, i.e., down light through the holes 35 in the housing,may be provided in a relatively simple, inexpensive and efficient manneras compared to the prior art.

Referring to FIG. 4, a second contemplated alternative embodiment of the"EXIT" type sign is depicted. The PC board 12 and row of LED lights 13are mounted by conventional means (not shown) at the bottom end 53 ofthe double sided sign enclosure or housing 54. The PC board 12 and LEDrow of lights 13 are oriented relative to housing 54 such that asubstantial portion of the light rays 55 and 56 radiate upwardly towardthe top end 57 of housing 54. A pair of oppositely facing reflectorplates 58, 59 are mounted above and aligned with the row of LED lights13. The bottom ends 60 of reflector plates 58, 59 are abutted togetherto form a relatively thin edge for splitting or partitioning orseparating the bundle of light rays 22 emitted from the LED lights 13.Reflector 58 is titled outwardly toward face plate or legend plate 61.Reflector 59 is tilted outwardly toward face (legend) plate 62. Eachreflector 58, 59, has a mirror like surface or specular reflectivesurface to effect light diffusing and dispersing therewithin. In theembodiment illustrated in FIG. 4, the bundle of light rays 22 is dividedinto substantially two equal and diverging bundles of light rays 55, 56.Each of these diverging bundles of light rays 55, 56 are diffused andreflected by reflectors 58, 59, respectively. In this manner thereflected light rays 55, 56, generate a substantially uniformillumination within each sign side 64, 65, respectively. Thus, the signlegend or characters or letters (not shown) are substantially uniformlyilluminated. It should be recognized that the reflectors or Baffles 14,58, 59 are somewhat rectangularly shaped and slightly smaller in sizethan the housing.

Referring now to FIG. 5, another alternative embodiment is illustrated.This embodiment features a double sided housing 54 having oppositelyfacing sign plates or legend panel 61, 62. An enlarged PC board 70 ismounted at the top end 57 of sign 72. Two spaced apart rows 73, 74, eachcontaining a plurality of LED lights are mounted on PC board 70. The LEDlights are directed downwardly within housing 54 by conventional means(not shown). The reflectors 58, 59 are joined or abutted together alongtheir top edges 75 and diverge outwardly. In this manner, light rays 76are diffused and reflected off reflector 58 to effect a substantiallyuniform illumination on legend plate 61. Light rays 77 are diffused andreflected off reflector 59 to effect a substantially uniformillumination on legend plate 62. Thus, reflector plates 58, 59 generallyextend downwardly the full length of display sign 72 and have a bent endsection 29 at its bottom. Bent end sections 29 are contoured to reflectemitted light rays 80, 81, into legend plates, 61, 62, respectively. Theinternal or back surfaces of the opaque area of legend plates 61, 62,respectively, are coated 82, 83 with a reflective coating to reflect thelight rays striking the opaque regions to, thereby, enhance theuniformity of illumination within each separate chamber or side displaypanel 84, 85, respectively.

It should be recognized that the prior art LED "EXIT" signs use largeprinted circuit boards arranged parallel to the legend face plate andhave many light bulbs which emit light rays directly unto the legendface plate. Such prior art signs have presented numerous disadvantages,such as, for example:

High cost for materials

Relatively high Energy Consumption

Down lights requires additional components

Relatively uneven illumination and spotted legend light effects

Defective bulbs resulting in noticeable sign defect

IN TOTAL CONTRAST to the prior art "EXIT" type signs, the presentinvention provides a relatively small PC board module with LED'soriented to provide indirect illumination of the sign legends. Theplacement, size, orientation and other features of the present inventivesign provide the following benefits and improvements over the prior artsigns.

1. Illumination board perpendicular to the face provides indirect evenillumination to the legend (no hot spots).

2. A minimal amount of LED's are required therefore a minimum surfacearea of PC board material is required.

3. Down light (light through bottom of enclosure) is accomplishedautomatically and without the use of costly additional component.

4. With better performance and less components, a savings is alsoachieved in energy (power) consumption.

5. Because the illumination module is small, the enclosure can besmaller and therefore less costly to manufacture.

While there has been shown what is considered to be the preferredembodiment and several alternative embodiments of the invention, it isdesired to secure in the appended claims all modifications as fallwithin the true spirit and scope of the invention.

What is claimed is:
 1. A sign assembly comprising:a housing defining anenclosure therein and having a screen means with an opaque wall sectionand a translucent legend portion defining indicia; a printed circuitboard mounted within said enclosure and arranged generally perpendicularto said screen means and generally at a side of said housing, said sideadjoining said screen means; a plurality of light emitting diode lampmeans mounted on said printed circuit board to radiate a bundle ofsubstantially unidirectional light rays generally transversely acrosssaid enclosure to illuminate said enclosure; and a reflector means fordiffusing and reflecting a portion of said bundle of light rays througha portion of said translucent legend portion of said screen means.
 2. Asign assembly as in claim 1, wherein: the legend portion defines theword "EXIT".
 3. A sign assembly as in claim 1, wherein: the legendportion defines a word.
 4. A sign assembly as in claim 1, wherein: thelegend portion defines a word.
 5. A sign assembly as in claim 1,wherein: the opaque wall section being light reflective within saidenclosure.
 6. A sign assembly as in claim 1, wherein: the printedcircuit board generally has an elongate rectangular configuration andhaving a normal angularity to said screen means.
 7. A sign assembly asin claim 1, wherein: the reflector means (13) comprises a flat sheetmaterial having a reflective surface (28) and being bent upwardly at oneend portion (29).
 8. A sign assembly as in claim 1, wherein: the legendportion of the screen means defines a perimeter dimension, and thereflector means has a size and configuration generally correspondingwith said perimeter dimension.
 9. A sign assembly as in claim 1,wherein: the reflector means being mounted at a predetermined anglerelative to said screen means.
 10. A sign assembly as in claim 1,wherein: the housing has a wall member having a reflective specularfinish means for serving as a reflector (30, 32) for diffusing andreflecting a light beam (22) onto said screen means.
 11. A sign assemblyas in claim 1, including: a housing wall section defining a hole (47) toenable one or more down beams of light rays (44) to exit said housing,said hole being located in a generally opposite side of said housingrelative to said printed circuit board and facing said printed circuitboard to receive the unidirectional light rays therethrough.
 12. A signassembly in combination, comprising:a housing (10) having a pair of sidewalls, a pair of top and bottom walls and a rear wall (17) defining anenclosure therein and having a front open wall portion; a cover plate(11) formed from a flat sheet of translucent plastic and dimensioned forbeing affixed to said housing over said front open wall portion,portions (21) of said cover plate being opaque, and said cover platehaving translucent portions (20) to define the word "EXIT"; a printedcircuit board means having a plurality of light emitting diodes mountedthereon and being mounted within said enclosure for providing a sourceof substantially unidirectional illumination (22, 76, 77), said printedcircuit board means being mounted at a side end of said enclosure, saidprinted circuit board being generally perpendicular relative to saidcover plate whereby said illuminating light rays (22) are radiatedoutwardly substantially parallel with said cover plate within saidenclosure to illuminate said enclosure; a reflector member (14) having asize and shape slightly smaller than said cover plate and having anupturned section (29), said reflector member being mounted within saidenclosure with a general diagonal arrangement for reflecting anddiffusing said parallel light rays (25) through said translucentportions of said cover plate.
 13. An EXIT type sign assembly,comprising:a housing (54) defining an enclosure (84, 85) and having apair of spaced apart cover screen means, each having an opaque wallsection and a translucent legend section (82, 83) for defining indiciaon each said legend section thereby providing a sign on two sides ofsaid housing; a printed circuit board means having two separated rowseach containing a plurality of light emitting diodes mounted thereon andbeing mounted within said enclosure for providing two rows of light rays(76, 77), said printed circuit board means being disposed at one end ofsaid enclosure, said printed circuit board being substantiallyperpendicular to both said cover screen means such that two spaced apartsubstantially unidirectional beams of light rays (76, 77) are radiatedtransversely across said enclosure to illuminate said enclosure; a pairof diverging reflector means (58, 59) each having a reflective surfaceand oppositely bent end members for diffusing and reflecting said lightrays (76, 77) through a portion of each respective legend section.